JBL Algol - 100ML

JBL Algol is a liquid algicide for freshwater aquariums. JBL sells it as a fast-acting treatment against algae in a tank that has got away from you.

Key Features

• Liquid algae treatment: dosed into the water rather than added to the filter.
• For freshwater aquariums: not sold for marine tanks.
• Two bottle sizes: 100ml and 250ml, so a small tank is not stuck with a large bottle.
• Dose by water volume: work out the litres you actually have, not the tank's advertised size. Substrate, rock and equipment take up a surprising amount of it.
• Test, then treat: a reading before and after tells you whether the dose did anything. Treating blind is how tanks end up over-dosed.
• Follow the pack dose exactly: an algicide is one of the few aquarium products where more is actively worse.

Before You Dose

• Scrape, siphon and net out as much algae as you physically can first. Less algae to kill means less of it breaking down in the water afterwards.
• Clean the filter and do a water change, so the tank starts from a clean baseline.
• Add extra aeration and keep it running. Dying algae use oxygen as they break down, and that is what actually harms fish after an algae treatment.
• Remove any carbon from the filter, or it will strip the treatment straight back out.

After You Dose

• Siphon out the dead algae over the following days rather than leaving it to rot.
• Do a water change at the end of the treatment, and test ammonia and nitrite in case the die-off has knocked the filter.
• Then fix the cause. Too much light, too long a photoperiod, too much feeding or a nitrate and phosphate surplus is behind nearly every algae problem, and an algicide treats none of them.

Good To Know

• Chemical algae treatments can harm shrimp, snails, crayfish and other invertebrates, and some plants resent them. Read the pack and do not use it in an invertebrate tank unless the label says it is safe.
• Never dose it alongside a medication, a bacterial starter or another algae product.
• Keep the bottle closed, cool, out of the sun and well away from children and pets.
• No algicide fixes an algae problem on its own. If nothing changes about the light and the nutrients, the algae comes back.